U.S. patent application number 11/346509 was filed with the patent office on 2007-08-23 for snowmobile and stopper mechanism for snowmobile.
Invention is credited to Shinnosuke Moji.
Application Number | 20070193801 11/346509 |
Document ID | / |
Family ID | 38427014 |
Filed Date | 2007-08-23 |
United States Patent
Application |
20070193801 |
Kind Code |
A1 |
Moji; Shinnosuke |
August 23, 2007 |
Snowmobile and stopper mechanism for snowmobile
Abstract
A snowmobile includes a handlebar controlling the direction of a
pair of skis, a link mechanism transferring a rotation movement of
the handlebar, a conversion mechanism connected to the link
mechanism and converting a movement of the link mechanism into a
movement including a vector in a vehicle body width direction of
the snowmobile, and a tie rod coupled to the conversion mechanism
and transferring the movement of the conversion mechanism to the
skis. A stopper mechanism is provided between the tie rods and the
link mechanism to regulate an external force applied from the
skis.
Inventors: |
Moji; Shinnosuke; (Shizuoka,
JP) |
Correspondence
Address: |
YAMAHA HATSUDOKI KABUSHIKI KAISHA;C/O KEATING & BENNETT, LLP
8180 GREENSBORO DRIVE
SUITE 850
MCLEAN
VA
22102
US
|
Family ID: |
38427014 |
Appl. No.: |
11/346509 |
Filed: |
February 2, 2006 |
Current U.S.
Class: |
180/190 |
Current CPC
Class: |
B62M 2027/026 20130101;
B62M 27/02 20130101 |
Class at
Publication: |
180/190 |
International
Class: |
B62M 27/02 20060101
B62M027/02 |
Claims
1. A snowmobile comprising: a pair of skis attached to a front
portion of the snowmobile; a handlebar arranged to control the
direction of the skis; a link mechanism arranged to transfer a
rotational movement of the handlebar; a conversion mechanism
connected to the link mechanism and arranged to convert a movement
of the link mechanism into a movement including a vector in a
vehicle body width direction of the snowmobile; tie rods coupled to
the conversion mechanism and arranged to transfer the movement of
the conversion mechanism to the skis; and a stopper mechanism
provided between the tie rods and the link mechanism to regulate an
external force applied from the skis.
2. The snowmobile of claim 1, wherein the conversion mechanism
operates as the stopper mechanism, the stopper mechanism including
a main arm pivot connecting the link mechanism to the tie rods, and
a secondary arm pivot arranged in a rotational range of the main
arm pivot to restrict a rotational movement of the main arm
pivot.
3. The snowmobile of claim 2, wherein the main arm pivot and the
secondary arm pivot are arranged adjacent to each other.
4. The snowmobile of claim 2, wherein opposing surfaces of the main
arm pivot and the secondary arm pivot contact each other so as to
restrict the rotational movement of the main arm pivot.
5. The snowmobile of claim 1, wherein the stopper mechanism
includes an arm pivot connecting the link mechanism and the tie
rods, and a stopper restricting a rotation of the arm pivot.
6. The snowmobile of claim 1, wherein a handlebar stopper restricts
a rotation movement of the handlebar, and the handlebar stopper is
provided on the link mechanism or on the side of the handlebar.
7. The snowmobile of claim 1, wherein the skis are connected to a
vehicle body frame of the snowmobile through a suspension.
8. The snowmobile of claim 1, wherein the skis are coupled to the
tie rods through knuckles.
9. The snowmobile of claim 1, further comprising a double wishbone
type suspension including an upper arm and a lower arm connected to
each of the skis.
10. A stopper mechanism for a snowmobile comprising: a rod that is
arranged to rotate with a rotation movement of a handlebar; a main
arm pivot connected to the rod; a secondary arm pivot arranged
adjacent to the main arm pivot to restrict rotation of the main arm
pivot; and a connection member arranged to connect the main arm
pivot and the secondary arm pivot to tie rods.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a snowmobile, in particular
to a stopper mechanism for a snowmobile.
[0003] 2. Description of the Related Art
[0004] A snowmobile is a vehicle for traveling on snow, in
particular, the snowmobile runs on the surface of snow via a track
belt, to which a driving force is transferred from an engine, and a
pair of skis attached to the front of the vehicle body. The skis of
the snowmobile can be rotated by a steering mechanism operated by a
rider. The mechanism with which the steering rotates the skis is
disclosed in e.g., U.S. Pat. No. 3,825,086; U.S. Pat. No.
4,826,184; U.S. Pat. No. 6,234,262; and U.S. Pat. No.
5,992,552.
[0005] The snowmobile often has a steering stopper attached to a
link suspension so as to prevent the skis from rotating more than
required. The steering stopper of the snowmobile usually uses two
stoppers, a knuckle side stopper provided in a knuckle supporting
the ski and a handlebar side stopper provided on the side of a
handlebar.
[0006] The handlebar side stopper regulates excessive input from
the handlebar caused by human operation and serves to prevent
breakage of the steering system. On the other hand, the knuckle
side stopper regulates a rotation direction during the handlebar
operation and serves to prevent breakage of the steering system due
to forces applied from the skis during full steering rotation of
the vehicle. The steering stopper is designed such that the knuckle
side stopper contacts a predetermined location around the knuckle
before the handlebar side stopper operates and makes contact, in
order to prevent breakage of the steering system due to forces
applied from the skis.
[0007] However, the inventors discovered that there were some cases
in which the knuckle side stopper was not exactly in contact with a
predetermined location around the knuckle depending on a stroke
(range of motion) of a front suspension. More specifically, in the
case of a double wishbone type snowmobile including an upper arm
and a lower arm, it often occurs that a rotation angle of the ski
changes with the stroke of the front suspension and the knuckle
side stopper is not in contact with the predetermined location
around the knuckle, and thus the knuckle side stopper fails to
function.
[0008] Even when the knuckle side stopper is not in contact with
the predetermined location around the knuckle, the rotation of the
ski can be controlled by the handlebar side stopper. However, in
the situation where the knuckle side stopper is not in contact with
the predetermined location around the knuckle, breakage of the
steering system may not be prevented. In order to prevent breakage
of the steering system, and also taking into consideration of the
situation where the knuckle side stopper is not in contact with the
predetermined location, it is necessary to increase the strength of
a link system so as to withstand a reaction force applied from the
skis during the vehicle rotation. However, increasing the strength
of the link system might lead to an increase in the cost of the
material and complexity of structure, and thereby lead to an
increase in overall cost.
SUMMARY OF THE INVENTION
[0009] In order to overcome the problems described above, preferred
embodiments of the present invention provide a stopper mechanism
for a snowmobile which is more suitable for the snowmobile.
[0010] The snowmobile according to a preferred embodiment of the
present invention is a snowmobile of the type running on a snow
surface via a track belt, to which a driving force is transferred
from an engine, and a pair of skis attached to a front portion of a
vehicle body, the snowmobile including a handlebar controlling the
direction of the skis, a link mechanism transferring a rotation
movement of the handlebar, a conversion mechanism connected to the
link mechanism and converting a movement of the link mechanism into
a movement including a vector in a vehicle body width direction of
the snowmobile, and a tie rod coupled to the conversion mechanism
and transferring the movement of the conversion mechanism to the
ski, wherein a stopper mechanism regulating an external force
applied from the skis is provided between the tie rod and the link
mechanism.
[0011] In a preferred embodiment of the present invention, the
conversion mechanism serves as the stopper mechanism, the stopper
mechanism including a main arm pivot connecting a rod, which
transfers the movement of the link mechanism, and the tie rod, and
a secondary arm pivot arranged in a rotation range of the main arm
pivot and restricting a rotation movement of the main arm
pivot.
[0012] Preferably, the main arm pivot and the secondary arm pivot
are arranged adjacent to each other.
[0013] In another preferred embodiment, opposing surfaces of the
main arm pivot and the secondary arm pivot are in contact with each
other to restrict the rotation movement of the main arm pivot.
[0014] In another preferred embodiment, the stopper mechanism
includes an arm pivot connecting a member which transfers the
rotation movement of the link mechanism and the tie rod, and a
stopper restricting a rotation of the arm pivot.
[0015] In another preferred embodiment, a handlebar stopper
restricting a rotation movement of the handlebar is provided on the
link mechanism or on the side of the handlebar rather than the link
mechanism.
[0016] In another preferred embodiment, the skis are connected to a
vehicle body frame of the snowmobile through a suspension.
[0017] In another preferred embodiment, the skis are coupled to the
tie rod through a knuckle.
[0018] In another preferred embodiment, the snowmobile is a double
wishbone type snowmobile including an upper arm and a lower
arm.
[0019] The stopper mechanism for the snowmobile according to a
preferred embodiment is a stopper mechanism controlling a rotation
angle of a pair of skis and includes a rotatable rod associated
with a rotation movement of a handlebar, a main arm pivot connected
to the rod, a secondary arm pivot arranged adjacent to the main arm
pivot and restricting a rotation of the main arm pivot, and a
connection member connecting the main arm pivot and the secondary
arm pivot to a tie rod.
[0020] In the present preferred embodiment, the stopper mechanism
regulating an external force applied from the skis is provided
between the conversion mechanism, which converts the movement of
the link mechanism transferring the rotation movement of the
handlebar, and the tie rod transferring the movement of the
conversion mechanism to the ski. Therefore, the knuckle side
stopper is always in contact with the predetermined location by the
stroke of the suspension. As a result, a more suitable stopper
mechanism for the snowmobile can be provided.
[0021] Other features, elements, steps, characteristics and
advantages of the present invention will become more apparent from
the following detailed description of preferred embodiments of the
present invention with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a perspective view showing an example of a
snowmobile according to a preferred embodiment of the
invention.
[0023] FIG. 2 is a perspective side view showing an example of the
structure of the snowmobile according to the preferred embodiment
of FIG. 1.
[0024] FIG. 3A is a perspective view showing the structure around a
handlebar, a link mechanism, and a pair of skis 11, and FIG. 3B is
a top view thereof.
[0025] FIG. 4 is a perspective view showing the relationship of the
handlebar, the link mechanism, a conversion mechanism, and a tie
rod in more detail.
[0026] FIG. 5 is a perspective view showing the conversion
mechanism and a stopper mechanism of the preferred embodiment of
FIG. 1.
[0027] FIGS. 6A to 6C are top views showing an operation of the
conversion mechanism and the stopper mechanism of the preferred
embodiment of FIG. 1.
[0028] FIG. 7A is a perspective view showing the position of each
mechanism during forward driving, and FIG. 7B is a top view
thereof.
[0029] FIG. 8A is a perspective view showing the position of each
mechanism when the handlebar turns to the left, and FIG. 8B is a
top view thereof.
[0030] FIG. 9A is a perspective view showing a location
relationship of each mechanism when the handlebar turns to the
right, and FIG. 9B is a top view thereof.
[0031] FIGS. 10A to 10C are top views showing variations of the
conversion mechanism and the stopper mechanism according to the
preferred embodiment of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] The inventors of the present invention discovered that a
rotational stopper mechanism that minimizes external forces applied
from the skis (reactive forces from the snow) can be more readily
achieved by providing the stopper around each of the right and left
knuckles. The inventors have also made intensive examination of a
stopper mechanism that is capable of functioning regardless of the
stroke (range of motion) of the front suspension, which is
different from merely increasing the strength of the stopper
mechanism.
[0033] Specifically, the inventors considered the mechanism in
which excessive inputs were prevented from being applied to the
steering system by keeping the relationship between the knuckle
side stopper and the handlebar side stopper at the same state so
that the knuckle side stopper can be operated first, regardless of
the stroke (range of motion) of the front suspension. As a result,
the inventors discovered that even without providing the stopper
around each of the right and left knuckles, the phenomenon in which
the knuckle side stopper fails to be in contact due to the stroke
of the suspension can be prevented, as long as the stopper
mechanism is provided between the conversion mechanism, which
converts the movement of the link mechanism transferring the
rotation movement of the handlebar, and the tie rod, which
transfers the movement of the conversion mechanism to the skis.
[0034] Hereafter, with reference to the drawings, preferred
embodiments of the invention will be described. In the drawings,
the elements having substantially the same function are denoted by
the same reference numerals to facilitate description. The
invention is however not limited by the following preferred
embodiments.
[0035] A snowmobile 100 according to a preferred embodiment of the
present invention will be described with reference to FIGS. 1 and
2. FIG. 1 is a perspective view showing an example of the
snowmobile 100 of the present preferred embodiment. FIG. 2 is a
perspective side view showing an example of a structure of the
snowmobile 100 of this preferred embodiment.
[0036] The snowmobile 100 of the present preferred embodiment
includes a track belt 16 to which a driving force is transferred
from an engine 15 and a pair of skis 11 attached to the front
portion of a vehicle body, and runs on snow with the track belt 16
and the pair of skis 11. The direction of the skis 11 is controlled
by a handlebar 10 operated by a rider.
[0037] A rotational movement of the handlebar 10 is transferred by
a link mechanism, and a movement of the link mechanism is converted
into a movement including a vector in the vehicle body width
direction of the snowmobile 100 by a conversion mechanism, that is,
in a direction to the left or the right. The link mechanism and the
conversion mechanism will be described below.
[0038] Each ski 11 is coupled to a vehicle body frame (body) 19 via
a knuckle 12 and a front suspension 13. The front suspension 13 of
the present preferred embodiment is preferably a double wishbone
type. The double wishbone suspension 13 can provide a stable shock
absorbing capability and terrain following capability even in a
high load state.
[0039] The engine 15 is mounted on the front end of the vehicle
body frame 19. The engine 15 of the present preferred embodiment is
preferably a 4-stroke engine, but it can also be a 2-stroke engine.
The 4-stroke engine has the advantages of having clean exhaust gas
and a quiet engine sound. On the other hand, the 2-stroke engine
has the advantages of being light weight, having high output, and a
good low temperature start-up. A fuel tank 18 is provided above and
to the rear of the engine 15. The handlebar 10 is arranged in front
of the fuel tank 18, and a seat 17 is arranged behind the fuel tank
18.
[0040] The track belt 16 to which the driving force is transferred
from the engine 15 is a propulsion unit particular to the
snowmobile and has an endless track structure. In the track belt
16, a rear suspension 14 is provided. The rear suspension 14 holds
the track belt 16.
[0041] Next, with reference to FIGS. 3A and 3B, the link mechanism
and the conversion mechanism of the present preferred embodiment
will be described, and with reference to FIG. 4, the stopper
mechanism of the present preferred embodiment will be
described.
[0042] FIG. 3A is a perspective view showing the structure around
the handlebar 10, a link mechanism 20, and the pair of skis 11, and
FIG. 3B is a top view thereof. In FIG. 3B, a conversion mechanism
30 and a tie rod 40 are also illustrated. FIG. 4 is a perspective
view showing the relationship of the handlebar 10, the link
mechanism 20, the conversion mechanism 30, and the tie rod 40 in
more detail.
[0043] The handlebar 10 which a rider operates is connected to the
link mechanism 20, and the rotational movement of the handlebar 10
is transferred to the link mechanism 20. The link mechanism 20 is
connected to the conversion mechanism 30, and movements 21a, 21b of
the link mechanism 20 are converted into a movement including a
vector in the vehicle body width direction by the conversion
mechanism 30. The movement including a vector in the vehicle body
width direction converted by the conversion mechanism 30 is for
pushing and pulling the knuckle 12. In the illustrated example, the
movement is generally a combined movement of a straight line
movement and a rotational movement.
[0044] The tie rod 40 is coupled to the conversion mechanism 30,
and the movement of the conversion mechanism 30 is transferred to
the pair of skis 11 through the tie rod 40. In the structure of the
present preferred embodiment, each ski 11 is coupled to each tie
rod 40 through the knuckles 12. In addition, each ski 11 is
connected to the vehicle body frame 19 through the suspension 13.
Being a double wishbone type, the suspension (front suspension) 13
of the present preferred embodiment includes an upper arm 13a, a
lower arm 13b and a shock absorber 13c.
[0045] Moreover, a handlebar side stopper 23 controlling the
rotational movement of the handlebar 10 is provided between the
link mechanism 20 and the handlebar 10. The handlebar side stopper
23 may be provided as a part of the link mechanism 20, or may also
be provided upstream of the link mechanism 20 (e.g., downstream of
the handlebar 10 or in a portion of the handlebar 10).
[0046] In the snowmobile 100 of the present preferred embodiment, a
stopper mechanism 50 is provided between the tie rod 40 and the
link mechanism 20, and the stopper mechanism 50 can regulate an
external force applied from the pair of skis 11. Specifically, the
kinetic energy input from the pair of skis 11 by a reactive force
from the snow surface can be distributed and received by the
stopper mechanism 50 provided between the tie rod 40 and the link
mechanism 20, thereby alleviating excessive forces from extending
to the link mechanism 20. As a result, the external force applied
from the pair of skis 11 which is alleviated by the stopper
mechanism 50 is transferred to the link mechanism 20 without
increasing the complexity more than necessary or using an expensive
material for the link mechanism 20 so as to increase the strength
of the link mechanism 20. Therefore, the link mechanism 20 and/or
the steering system can be simplified.
[0047] Since the stopper mechanism 50 of the present preferred
embodiment is provided between the tie rod 40 and the link
mechanism 20, it is possible to prevent the knuckle side stopper
from not being in contact with the predetermined location by the
stroke of the front suspension 13, unlike the case where the
stopper is provided around the knuckle 12. In other words, by
providing the stopper mechanism 50 upstream of the tie rod 40
instead of on the side of knuckle 12 downstream of the tie rod 40,
the stopper mechanism 50 can readily operate before the handlebar
side stopper 23 regardless of the stroke (range of motion) of the
front suspension 13, and as a result, excessive input can be
prevented from being applied to the steering system.
[0048] In other words, since the stopper mechanism 50 of the
present preferred embodiment is not arranged on the knuckle 12,
even when the rotation angle of the pair of skis 11 is changed by
the stroke of the front suspension 13, the movement of the stopper
mechanism 50 can be assured regardless of the change in the
suspension.
[0049] In addition, in the structure of the present preferred
embodiment, since the knuckle side stoppers which are provided
around each of the right and left knuckles 12 are replaced with a
center stopper mechanism 50, the motion of the pair of skis 11 can
be more accurately regulated.
[0050] Next, with reference to FIG. 5, the conversion mechanism 30
and the stopper mechanism 50 of the present preferred embodiment
will be further described. FIG. 5 is a perspective view showing the
conversion mechanism 30 and the stopper mechanism 50.
[0051] In an example of the present preferred embodiment, a feature
of the conversion mechanism 30 serves as the stopper mechanism 50.
In other words, the present preferred embodiment utilizes a
mechanism that performs both the functions of the conversion
mechanism 30 and the stopper mechanism 50. Therefore, various
advantages, e.g., a reduction in the number of components and cost
achieved by utilizing common components, can be achieved.
[0052] The stopper mechanism 50 includes a main arm pivot 51 and a
secondary arm pivot 52 restricting rotation of the main arm pivot
51. The main arm pivot 51 connects the rod 22, which transfers the
movement (21b in FIG. 4) of the link mechanism 20, and the tie rod
40. The secondary arm pivot 52 is arranged in the rotation range of
the main arm pivot 51 in the example shown in FIG. 5.
[0053] In particular, the main arm pivot 51 and the secondary arm
pivot 52 are arranged adjacent to each other. The opposing surfaces
51a, 52a of the main arm pivot 51 and the secondary arm pivot 52
are in contact with each other, thereby restricting the rotation of
the main arm pivot 51.
[0054] In the example shown in FIG. 5, a connection member 54
connects the main arm pivot 51 and the secondary arm pivot 52 to
the tie rod 40. Since the main arm pivot 51 and the secondary arm
pivot 52 are connected to the right and left tie rods 40 via the
connection member 54, the rotation movement of the rod 22 in both
the right and left directions can be converted into the movement
including a vector in the vehicle body width direction.
[0055] Next, with reference to FIGS. 6A to 6C, the operations of
the conversion mechanism 30 and the stopper mechanism 50 of the
present preferred embodiment will be described. Note that the rod
22 is located on the right hand side in each of FIGS. 6A to 6C, but
it can also be located on the left hand side.
[0056] First, when the snowmobile is moving forward, as shown in
FIG. 6A, the main arm pivot 51 and the secondary arm pivot 52 are
parallel to the forward direction of the vehicle body, and the main
arm pivot 51 and the secondary arm pivot 52 are not in contact with
each other.
[0057] Next, when the handlebar is turned to the right, as shown in
FIG. 6B, the main arm pivot 51 is in contact with the secondary arm
pivot 52 so that the rotation of the main arm pivot 51 is
restricted. Specifically, a portion of the inner surface 51a of the
main arm pivot 51 is in contact with a portion of the inner surface
52a of the secondary arm pivot 52 so that the rotation of the main
arm pivot 51 is restricted.
[0058] Note that in the structure of the present preferred
embodiment, the opposite surfaces 51a, 52a of the arm pivots 51, 52
are in contact with each other at a position far apart from the rod
22. This is because contact at a distant point can decrease the
influence of tolerance (error) as compared with contact at a close
point.
[0059] Moreover, in order for the surfaces to come into contact at
such a distant point, as shown in FIG. 6B, the structure is
designed such that portions of the arm pivots 51, 52 that are
closer to the rod 22 are not in contact with each other even when
the handlebar is turned to the right.
[0060] FIG. 6B shows the case where the handlebar is turned to the
right, whereas FIG. 6C shows the case where the handlebar is turned
to the left. It is conventional to perform a treatment (e.g., heat
treatment) to increase the surface hardness such that the contact
surfaces 51a, 52a of the arm pivots 51, 52 do not wear out and
degrade their accuracy. A material with a high hardness may be
used. But, the use of such a material may increase the material
cost and processing cost of the material. Hence, it is conventional
to perform a treatment (e.g., heat treatment) to increase the
surface hardness for the contact surfaces 51a, 52a of the arm
pivots 51, 52.
[0061] Next, with reference to FIGS. 7A to 9B, the relationship of
the handlebar 10, the link mechanism 20, the conversion mechanism
30, the stopper mechanism 50, the tie rods 40, and the knuckles 12
will be described.
[0062] FIG. 7A is a perspective view showing the position of each
mechanism during forward driving, and FIG. 7B is a top view
thereof. As shown in FIGS. 7A and 7B, the handlebar 10 is not
turned in any direction when the snowmobile is moving forward, and
thus the main arm pivot 51 and the secondary arm pivot 52 are
parallel to each other along the forward direction of the vehicle
body. Accordingly, the right and left tie rods 40 and the knuckles
12 are symmetrically arranged.
[0063] On the other hand, FIG. 8A is a perspective view showing the
position of each mechanism when the handlebar 10 is turned to the
left, and FIG. 8B is a top view thereof. As shown in FIGS. 8A and
8B, in this situation, the main arm pivot 51 and the secondary arm
pivot 52 are in contact with each other to restrict the rotation
thereof. Specifically, when the handlebar 10 is turned to the left
over a predetermined angle, the stopper mechanism 50 disperses the
external force applied from the pair of skis 11 and alleviates the
transfer of the force to the link mechanism 20, regardless of the
behavior of the front suspension. Since the handlebar 10 is turned
to the left, the conversion mechanism 30 operates to pull in the
left tie rod 40 and push out the right tie rod 40 thereby turning
the left and right knuckles 12 to the left.
[0064] On the contrary, FIG. 9A is a perspective view showing the
location relationship of each mechanism when the handlebar 10 is
turned to the right, and FIG. 9B is a top view thereof. As shown in
FIGS. 9A and 9B, in this situation, the main arm pivot 51 and the
secondary arm pivot 52 are in contact with each other to restrict
the rotation thereof. When the handlebar 10 is turned to the right
over a predetermined angle, the stopper mechanism 50 is
operated.
[0065] Since the handlebar 10 is turned to the right, the
conversion mechanism 30 operates to pull in the right tie rod 40
and push out the left tie rod 40 thereby turning the left and right
knuckles 12 to the right.
[0066] Preferred embodiments of the invention have been described
above, but the invention should not be limited to the
aforementioned description and various modifications are
possible.
[0067] For example, the conversion mechanism 30 and the stopper
mechanism 50 may be composed of separate units and the arm pivots
may be integrated. FIGS. 10A to 10C show a modified example of the
conversion mechanism 30 and the stopper mechanism 50 of the
preferred embodiments of the invention described above. FIG. 10A
illustrates the forward driving state and FIGS. 10B and 10C
illustrate either of the states where the handlebar 10 is turned to
the left or the right.
[0068] The stopper mechanism shown in FIGS. 10A to 10C operates by
contacting the arm pivot 55 with the stoppers 57, 59. The arm pivot
55 connects members 25, 27 that transfer the rotational movement of
the link mechanism 20 and the tie rods 40. Note that the arm pivot
55 also defines the conversion mechanism 30 in the modified
example.
[0069] In the forward driving state shown in FIG. 10A, the arm
pivot 55 does not incline to any direction, and the tie rods 40 are
symmetrical. In the state shown in FIG. 10B, the stopper mechanism
is operated by contacting the arm pivot 55 with the stopper 57. On
the other hand, in the state shown in FIG. 10C, the stopper
mechanism is operated by contacting the arm pivot 55 with the
stopper 59.
[0070] While preferred embodiments of the present invention have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing the scope and spirit of the present invention. The scope
of the present invention, therefore, is to be determined solely by
the following claims.
* * * * *